On the New Host form, the Name field has an entire copy of the input_group_btn randomise button HTML stored as an input_group_btn attribute on the input field:

<div class="input-group"><input value="cobalt.example.com" input_group_btn="<a class=&quot;btn btn-default&quot; title=&quot;»Generate new random name. Visit Settings to disable this feature.«&quot; href=&quot;#&quot; onclick=&quot;randomizeName(); return false;&quot;><span class=&quot;glyphicon glyphicon-random &quot;></span> </a>" class="form-control " focus_on_load="true" type="text" name="host[name]" id="host_name"><span class="input-group-btn"><a class="btn btn-default" title="" href="#" onclick="randomizeName(); return false;" data-original-title="»Generate new random name. Visit Settings to disable this feature.«"><span class="glyphicon glyphicon-random "></span> </a></span></div>

The option isn't being deleted from the options hash in the field helper before being passed to the text field generator.